Câu 1: they are going to build a new school in this city.
=> a new school.......
Câu2: We didn't finish that work until yesterday.
=> It wasn't until....
Câu 1: they are going to build a new school in this city. => A new school is going to be built in this city. Câu2: We didn't finish that work until yesterday. => It wasn't until yesterday that we finished that work.